This invention relates to an end closure for a shake and pour container, and more particularly, to such a plastic end closure which has a break open frangible lid which, in its initial closed position, seals the container and which, in its subsequent open and reclosable position, controls access to the contents of the container.
Shake and pour containers are well known in the art, and are typically spiral wound paperboard containers with various liners and barriers incorporated therein to protect the product. Alternatively, the container may be molded of a suitable plastic resin or the like. Such containers are often utilized for grated cheese, coffee creamer, or other granular, flowable products. The plastic end closures for these shake and pour containers generally include a cover which is mounted on one end of a canister-type container and which has a frangible, push-open lid which is sealed to the cover when closed. When initially packaged and shipped, the push-open lid forms a tamper-evident seal with the end cover, preventing spillage or spoiling of the product. To open the shake and pour container, pressure is exerted upon the push-open lid, breaking the frangible seal lines forming the perimeter of the lid, and bending it into the container along a molded hinge line. Next, to prevent the product from spilling from the container or from spoiling, a rotatable closure pivotally secured to the cover is rotated to a closed position covering the opening formed by the lid. To dispense the product, the rotatable closure typically contains openings or gratings which may alternately be aligned with the push-open lid opening, thereby allowing the product to be dispensed from the shake and pour container at a controlled rate. Alternatively, a second hinged lid cover is provided which snaps securely in place over the opening formed by the push-open lid. When the product is to be dispensed from containers having this type of end closure, the second lid is unsnapped and bent upward, exposing the push-open lid opening and allowing the product to be poured or shaken out.
However, with such prior art plastic end closures, the molded in place hinge line of the push-open lid has a "memory" such that after the initial opening of the push-open lid, the lid tends to spring back at least partially towards its initial closed position, thus partially blocking the pouring or shaking of the product from the container. Additionally, the necessity of providing either an rotatable cover or second hinged lid adds to the complexity and manufacturing cost for the end closures.
In an effort to prevent such push-open plastic end closure lids from springing back and partially blocking the pouring opening, certain prior art closures were provided with means for engaging the push-open lid and retaining it in its fill open position. One such example of such the is disclosed in U.S. Pat. No. 4,969,572 which utilizes a tab on the underside of the frangible lid. This tab, when pushed to its fully open position, engages a gripping member molded on the underside of the cover to lock the lid in its fully open position. However, in use it has been found that consumers may not push the lid to its fully open position so that the locking tab engages the gripping member. Additionally, a second cover means is required to close the container for storage after the frangible seal of the push-open lid has been broken.
Accordingly, alternative means for holding the push-open lid in an open position have been developed. One such alternative end closure is described in U.S. Pat. No. 5,167,338 in which the push-open lid has a tab extending opposite the lid opening such that when in an open position, the tab extends upward from the end closure, and engages with a rotating cover, thereby holding the push-open lid in an open position. While providing a solution to the problem of "memory" in the push-open lid hinge, this end closure still requires a two piece manufacture, as a rotating cover is needed to secure the lid in an open position and to close the container for subsequent storage.